Crate 350 & Holley 1850...keep or ditch?

[Daubs]

The K-20 has a new crate engine and I've been experiencing off idle stumbling and even backfiring. Messed with timing and finally have it good-to-go (kept advancing until ping, then backed off, but engine still stumbles and even backfires at times).

So I google search the Holley 1850 and find this article: http://www.hotrod.com/techarticles/53058/

And I quote, "The problem with low manifold vacuum in the 1850 is it requires more idle throttle blade opening, which exposes most of the idle transfer slot to feed sufficient fuel to the engine to keep it running at idle. This often creates an overly rich idle mixture, which leads directly to a lean flat-spot just off-idle. This lean condition often leads to a backfire."

The article has some recommendations for solving this issue.

The big question is should I keep the Holley and work with her, or just ditch and get something else (Edelbrock, Q-jet, other?) It's the stock 350 crate engine with Edelbrock performer intake and Ram-Horn exhaust. Four speed manual tranny with 4.10 gears and glass packs on duals.

[crazy longhorn]

If you have the 290 hp crate,(L-82 cam) you might try hooking the distributors vacumn advance to to full manifold spot on the carb, to bring the vacumn up. You will find this trick listed in the Edelbrock website , for tuning with hot cams. It brings the idle speed up , allowing you to close the throttle blades, & cover part of the transfer slot @ idle. Best of luck.... L

[glock35ipsc]

For a stock motor, I still don't think you can beat a good stock Q-Jet (where is my nomex??!!), whether new (reman) or properly rebuilt. Or, a 600cfm Edelbrock with an electric choke will generally run good right out of the box.

[JAKES 68GMC]

I've had nothing but good luck from my 500 Holley. Everyone says that either they are junk or they are the greatest carb out there. All I did was bolt it on and adjust the idle down, and has run good ever since. We did have to re-time it, but it was way out of whack when I got it.

[Daubs]

Not the 290 HP cam, but the standard crate (listed anywhere from 190 to 260 HP).

I do have a Holley rebuild kit, but wanted to wait until I got the engine running.

[glock35ipsc]

9 times out of 10, if a Holley backfires, it will blow the power valve. If you have an extra, you might try to swap it out first.

[BrianJordan]

dump the holley and go with the edelbeock 600cfm.
just my 2 cents.

[Psycho71]

Holley, you'll either love it or hate it. No truer words have ever been spoken. If you are a tinkerer and want evry ounce of torque you can get, use a Holley. If you want something you can trow on there a run for ever w/o touching it. Use anything else. Actually I wouldn't know what else to recommend. I use Holleys!

Sounds like it could be a power valve failure but you have obviously done more research than I on this issue. Call the Holley tech line. It's what they are there for. These guys will put you right on the solution. If you just don't want to mess w/it, then get another carb.

Good luck,
Jay

[68Stepbed]

If you want a set it and forget it setup and run it's best, go with a 500 2-barrell Holley or a 500 Edelbrock. I have a 570 Street Avenger on the same engine, and it's a tad rich. We're fixing to solve that problem with a cam and heads though.

I don't think you want to hot rod this thing, so don't worry about a 500 cfm being too small. It's actually perfect for a stock 350 for the street. Excellent throttle response, driveability, and gas mileage. The best running engine I ever had was a stock 350 with a 500 Edelbrock. Man, I miss that thing too.

[Gray Ghost]

Another Edelbrock vote here. My Qjet runs ok, but a 1405 maunal choke carb is in my future.

[Daubs]

Well, the Holley is gone...and sitting atop the crate 350 is a brand new Edelbrock 1405. Problem solved!!!

Fired right up. I re-checked the timing and turned down the idle speed. Took her for a spin around the block and WOW!

For more, see the original post...

http://67-72chevytrucks.com/vboard/s...36#post1749936

[glock35ipsc]

I know have tthe 1405/1406 on two of my trucks, actually the 1406's. I put one on the 70 4x4 when it started acting up, and I put one on my 68 when I first got it. They are fantastic carbs!